This is a multicenter, outpatient, randomized, Phase I/II double-blind comparison of two double therapy regimens (zidovudine plus ddI and ddI plus nevirapine) and one triple therapy regimen (zidovudine, ddI, and nevirapine) in HIV-infected children and adolescents. This study is now closed to accrual after reaching the goal of 390 patients. We will continue to collect data from the study patients for the next 12 months. Data analysis is in progress.